Unable to add further datafile to an existing tablespace.

Hi frenz...

I'm unable to add a new datafile in an existing tablespace (eg. ACCTS).

SQL> alter tablespace ACCTS add datafile '/opt/oracle/oradata/ARM/check1.dbf' size 1000M
extent management local uniform size 256k;

I get the following error while executing the above statement.

ORA:00933 : SQL command not properly ended.

Please let me know what else can be done to create a datafile with extent size as 256k.

Thanks in advance.

remove everything after the 1000M, it is not needed and illogical

the tablespace sets the extent sizes, not the datafile